四川邮电职业技术学院教案专用纸 Teaching Content Contents Ti Apparatuses I. Revision Teacher can use the following questions to help the students to revise what they studied in the last unit I. What have we studied in the unit 1? loud speaker, Possible answers: the principle of PCM blackboard 2. What is PCM? Possible answers: an encoding method to transformed analog voice signal to one 3. Tell us the main operations of PCM? Possible answers: sampling, quantizing and coding II. Pre-reading Activities s mIns 1. Ask the Ss the following two questions related to the theme of the text 1)Can you enumerate what you contacted in the study of the courses including digital communications and switching technology? Possible answers: PCM, space division switching, time division switching time division multiplexing( TDM), etc 2) What is TDM? Possible answers: TDm is a scheme in which numerous signals are combined for transmission on a single communications line or channel. each signal is broken up into many segments, each having very short duration with any analog channels were digitized and it has became a popular way to deliver analog voice over digital networks 2. Teacher leads into the text by saying: From the explanation you gave about TDM It can be said that TDM lays very important groundwork for data communications Based on your knowledge about TDM, I'm sure, you can achieve a good understanding of the new text, asynchronous serial data transmission because it is closely related to TDM. Now, lets have a careful study of the text. (minute) II. While-reading activities New words and phrases mIns Page 2 of 7 Teaching Plan of Telecommunications English Unit 2四川邮电职业技术学院教案专用纸 Page 2 of 7 Teaching Plan of Telecommunications English Unit 2 Teaching Content Contents Time Teaching Apparatuses I. Revision Teacher can use the following questions to help the students to revise what they studied in the last unit. 1. What have we studied in the Unit 1? Possible answers: the principle of PCM 2. What is PCM? Possible answers: an encoding method to transformed analog voice signal to digital one. 3. Tell us the main operations of PCM? Possible answers: sampling, quantizing and coding. II. Pre-reading Activities 1. Ask the Ss the following two questions related to the theme of the text: 1) Can you enumerate what you contacted in the study of the courses including digital communications and switching technology? Possible answers: PCM, space division switching, time division switching , time division multiplexing( TDM), etc. 2) What is TDM? Possible answers: TDM is a scheme in which numerous signals are combined for transmission on a single communications line or channel. Each signal is broken up into many segments, each having very short duration. With TDM, many analog channels were digitized and it has became a popular way to deliver analog voice over digital networks. 2. Teacher leads into the text by saying: From the explanation you gave about TDM, It can be said that TDM lays very important groundwork for data communications. Based on your knowledge about TDM, I’m sure, you can achieve a good understanding of the new text, asynchronous serial data transmission because it is closely related to TDM. Now, let’s have a careful study of the text. (1minute) III. While-reading Activities i. New words and phrases 3 mins 5 mins 3 mins computer， projector， loud speaker， blackboard